Gear tooth face finishing apparatus and method



. July 18, 1944. 1:). A. WALLACE 2,353,861

GEAR TOOTH FACE FINISHING APPARATUS AND METHOD Filed June 20,- 1942 v 2 Sheets-Sheet 1 INVENTOR- FdVz J fZ/WZ/ace A W LQWw M ATTORNEY JE.

Ju1 1s, 1944. D. A. WALLACE 2,353,8 1

GEAR TOOTH FACE FINISHING APPARATUS AND METHOD Filed June 20, 1942 2 Sheets-Sheet 2 JNVENI'OR Fan .141 H, WaZZ4ce.

ATTORNEYS.

f: srA'rEs (PATENT I orrlcr.

em roo'rn race rmrsnmc arrana'rns m mrrnon Davld'A. Wallace, Detroit, assignor to Chrysler Corporation, Bighlandl'ark, Micln, a

- corporation of Delaware application June 20, 1942, sem No. 447,796

14 Claims. (01. 51-64) I .This' invention relates to an improved gear tooth surfaceiiinishing apparatus and method. More particularly, Jthe invention pertains to improvements in an apparatus and method for finishing the face surfaces of'gear teeth of diverse contours. by an abradlng action during a which are "produced'between such surfaces and an abrading member, simultaneous relative movements in ,a plurality of different directions injcludingjthe one in whichthe face surfaces of "meshedgear teeth move "relative to each other,

duringoperation; 4

"One of the main objectsof the invention is to provide gearteeth face surface finishing appa- Fig. 6 is a fragmentary plan view, partly in section, of a yieldable abrading element holder embodyinga modified form of the invention.-

Fig. 7 is afragmentary sectional view taken on the line 1-1 of jig. 1.

In the form of the invention illustrated in the drawings, the improved gear tooth face finishing apparatus comprises a frame-like base structure generally designated by the numeral III on which are mounted spaced bearin'g. blocks ll having registering vertically aligned bores therein. A vertically reciprocable shaft I2 is oscillatively iournalled in the bores of the blocks ii and pivotally connected at its lower end to a crank arm l3 by a universal joint element ll. The universal joint element ll has a flange II pivotally connected by a pin II to a bifurcated end portion-l1 on the lowerextremity of the shaft l2. The

universal'joint element It comprises a plate l8 having a downwardly extending stud i9 .lournalled in an aperture 20 formed in a web portion 2| provided at the upper end of the crank arm ii. The lower end of the crank arm I3 is joura geartooth andan abrading'element relative reciprocativefmo vements both depthwise and lengthwise of the'tooth and relative oscillative m,ovem'ent thereofaboutthe normal axis of the gear on-which it isprovided while the abrading element is .in contact with the face of the tooth. An additional object of the invention isto provide apparatus of this kind which produces the foregoing oscillative and reciprocative move- .ments at speeds of predetermined anddiffere'nt values.

Illustrative embodiments of the invention are shown'in the accompanying drawings in which:

Fig. 1 is a perspective view of gear tooth finishing apparatus embodying the invention andillustrating the performance of the improved method.

Fig. 2 is an enlarged, fragmentary perspective view of the tool and work holding-units of the apparatus shown in Fig. 1.

nailed on an eccentric 22 which is'driven through a gear unit 23 by a motor 24. The motor 24 is drivingly connected by pulleys 25 and 26 and a belt 21 to the driving shaft of the gear unit 23. The rotation of the eccentric 22 produces vertical reciprocatory movement of the shaft 12.

I The shaft I2 is drivingly oscillated by a motor 28 connected through pulleys 29 and 30 and a belt 3| with'a gear unit 32. The final driven shaft 33 of the gear unit 32 is disposed vertically, as

illustrated in Fig. l,- and provided at its upper L ing. a pin 3! extending between its vertically Fig. 31s a fragmentary sectional view taken on theline 33 of Fig. 2.

Fig. 4 is a fragmentary sectional view taken on thelineHofFig. 1. c

- Fig. 5 is an enlarged, fragmentary plan view showing the abrading elements: and gear tooth face surfaces, illustrated in Fig; l, in operative engagement. 3

end with a crank member having a crank pin 34.

Pivotally mounted on the crank pin 34 is a lever,

35 which-is supported at the left side of the apparatus, as viewed in Fig. 1, by a bracket 36 having a slot 31 therein in which the left end of the lever 33 is slidably mounted. The shaft I2 is operatively connected with the lever 35, intermediate the ends of the latter, by a yoke 33 havalignedarms and projecting through an aperture formed in the lever 35.; As the crank. pin

34 is revolved about the axis of the final driven shaft 33 it reciprocates the lever 35 thereby oscillating the shaft [-2 while it is simultaneously reciprocated by the eccentric 22, the space between the arms of the yoke 38 being suiiicient to accommodate this reciprocatory movement as the pin a slides vertically relative to the lever 35.

Mounted on the upper end of the shaft 12 is a work supporting late having a spindle ll extending upwardly'therefrom in co-axial alignmentwiththeoscillativeaxisoftheshaftfl. Th spindle It is adapted toreceive a gear 42 having a tooth 43 provided with face portions tobefinished. Thegearfl mayhereleasably heldinaflxedpositionwithrespecttotheshaft l2 and work supporting plate 0 by a suitable clamping collar is mounted on the upp m trated in Fig. 2 of the drawings is suitably fixed against movement relative to the spindle ll. It is thus simultaneously reciprocated vertically,

lengthwise of the gear teeth, and oscillated about the normal axis of the gear. 7

Mozmted on the top of the frame structure II is a plate ll having spaced guide rails 48 thereon between which is 'shiftably mounteda tool support member-S. The guide rails" are sopositioned as to confine reciprocative movement of the tool support member it to a path extending depthwise of the tooth I which is positioned for receiving a finishing operation. Mounted onthe shiftable tool support I! is a finishing tool generally designated by the numeral 5' which comprises a block II having a pair of abrading element holders I2 pivotally moimted thereon at 53 and It respectively.

Each holder 52 has an abrading element It ex tending outwardly therefrom and adapted toengage opposite face portions of the tooth 3 in embracing relationship as illustrated in Fig. 5. The outer end portions of the abrading elements 56 are shaped to conform generally'to the contour of the opposite face portions of the tooth 43. Each abrading'element holder 52 has a box-like structure I! on its forward end provided with a removable clamping plate "by which the abrading elements v56 are removably heldin place. A bolt 59 extends through registering apertures in the abrading element hold ers 52 and is provided on one'end with a spring 6| which may be adiustably compressed by a nut Ii threaded on the bolt for the p p e of resiliently yieldablyl urging the abrading element holders 52 toward each other about their pivots reciprocated in a direction generally depthwise of the gear tooth being finished by a motor ,2 mounted on the plate ll of the frame II. The

, motor 62 has a vertically disposed shaft 3 provided on its lower extremity, as illustrated in Fig. 4, with an eccentrlcally located driving-D ii. The driving pin 54 extends into a, a: slot 65 formed in a sbiftable cros head men "which is rigidly connected by a bar I! andblock 68 with the reciprocable tool slmpo member H, as illustrated inFlg.'l. Rotationof the motor shaft 63 reciproeates the cross head 6' which in turn reclprocates the tool support ii and the abrading tool structure carried thereoy. This action produces reciprocation of the abrading elements 5! in the direction of the depth of the tooth operated upon.

In. the preferred operation of the foreg e finishing apparatus the gearls reciproeated ax ially of its normal at" a rate: of fromgloo to 150 reciprocationsapm'minute and throughout a stroke dependingi the of the gear teeth being and the comparative:

width of the abradin'gelements it a gear of the inithedraw h1g5 with the aifl elements of the dimensions shown;v the stroke of reciprocative movement may one-fourth: of an: inch to three-eightllsmfi amin'ch' in'r The gear is simultaneously oscillated about its nor- 4 mal axis at a rate-'offrom 150 to 200 oscillations per minute throughout. an arc: of sufllcient' amplitude to bring" the abrading elements: into contact with substantially the full depth of the tooth face portions, The abrading' elements 5! are reciprocated 'generallydepthwi'se' of the: tooth operated upon at a rateoffrom 700 150 900reciprocations per minute and throughout a stroke of approximately one-sixteenth" of .an' inch. All of these reciprocative and oscillative' movements" are preferably simultaneously produced in order to distribute the abrading action uniformly over the entire face portions of the tooth and to avoid re-tracing the same path: by localized hard' points in the abmding'elementsi' The abradi'ng' elements are preferably applied to the: face portions of the tooth with:relativelylow pressure in the presence of a suitable: lubrlcantl when fin-- ishing with relatively low pressures by a multiplicity of movementsof' the above order and in: the presence of suitable: lubricants; the finishing operation removesonlytha't'portion oil the metal which has been by a prior machining or grinding operation and does: not significantly vary a previously established tooth face If desired, the oscillating: movement of the: gear and its reciprocative movement may beemployed while the abradingi elements are held. at rest or the gear'may'be" oscillated about its nor-; mal axis without reciprocating it while the abrading elements are: reciprocated depthwise of the tooth operated upon; It is however,. found that the best results are obtained by conducting the three foregoing relative movements between the work and" the elements simultaneously.

In the form of the invention illustrated in Fig; 8, a pair of series of leaf spring elements 15 are rigidly mounted at their rear ends on: the block 7 ii. The long leaves I! of series of leaf springs is provided with an abrading element holder Ii in which is: mounted an abrading element II. The abrading elements and the gear tooth operated upon with this form of the apparatus undergo the relative oscillative and reciprocative movements set forth above;

Although but several specific embodiments of the invention are herein shown; and described, it will be understood thatvarious changes in. the sequence of operations, steps and materials employed may be made without departing from the spirit of the invention,

Iclaim:

. 1. Gear tooth faceapperaws com-- prising relatively oecillatable and. reciprocable work and toolsupport members; means on said work support member for positioning a. of ages: havlng'a face portion; to be finished for receiving a finishing operatiom means: for confining the relative reciprocative movement of said members to a course extendlngdepthwi'se at 75 saidtooth and transversely oi: the axisof the:

. imity with respect to said face portion includin means for yieldably urging said element into mechanism for drivingly simultaneously repeatedlyproducing said reciprocative and oscillative movements at respectively different rates while said element is in abrading contact with the face I portionsof the same tooth. I

2. Gear tooth face-finishing apparatus comprising relatively oscillatable and reciprocable work and tool support members, means on said work support member for positioning a tooth of a gear having a face portion to. be finished for receiving a finishing operation, means for confining the relative reciprocative movement of said axis of the relative oscillative movement thereof. an abrading tool on said tool support member having an abrading element extending into contacting proximity with respect to said face portion including means for yieldably urging said abrading contact with said face portion, and

-members to a course extending parallel to the a;sss,ae1 3 ing an oscillatable work support member, means shiftably mounting said member for reciprocative movement substantially parallel to its oscillative axis, means on, said member for; mounting. a-gear for oscillation therewithabout its normal; axis and reciprocation therewith substantially to saidaxis and for positioning atooth of said having f ii e n shed, to receivea finishing operation, a tool support member, an abrading tool shiftably mounted on said tool support member for reciprocation transversely g of said axis depthwise of said toothincludingan abrading element extending into overlapping re lationship with respect to said toothandhavin means for urging said element into abrading en'- gagem'ent withsaid face portion, and mechanism. for drivingly simultaneously producing said (is-. cillativemovements said reciprocative movements in said direction parallel to said axis and a plurality of said transverse reciprocative movementsduring each half cycle of said oscillative-move; ments. 6. Gear tooth face finishing-appa atus com prising relatively oscillatable abrading and element into abrading contact with said face portion, and mechanism for drivingly simultaneously producing said reciprocative and oscillative movements at respectively different rates while said element is in abrading contact withv face portion of said tooth.

3. Gear tooth face finishing apparatus com prising tool and work support members, mechanism mounting said members for relative osc'illatable movements and stages of relative reciprocative movements in transverse directions, means on said work support members for positioning a tooth of a gear having a face portion to be finished for receiving a finishing operation, said mounting mechanism including means for confining one of said stages of reciprocative movemerit to a course extending normal to said axis and depthwise of said tooth and the other stage of reciprocative movement to a course extendin lengthwise of said tooth, an abrading tool on said tool support member having an abrading element extending into contacting proximity with respect to said face portion and including means for yieldably urging said element into abrading contact with said face portion, and

mechanism for drivingly simultaneously producing-said oscillative and said two stages of reciprocative movement at respectively different rates while said element is in an abrading conx tact with said face portion of said tooth.

4:. A gear tooth face finishing apparatus including an oscillatable work'support member, means on said member for mounting a gear for dscil- I lation therewith about a fixed axis coincident tooth and'having means for urigng said element into abrading engagement with-v said face portion, and mechanism fordrivingly simultaneously producing said oscillative movements and a plurality of said reciprocative movements during each half cycle of said. oscillative movements.

- 5. Gear tooth face finishing apparatus includis work support members, means on said work -sup-, port member for positioning atooth-oiPa-gear having a face portion to be finished for. receiv ing a finishing operation, anabrading tool holder shiftably mounted onsaidtool suppor for. IE, ciprocative movement depthwise i of said .tooth, an abrading element ,movablynmountedon said tool holder and extending into contacting pro'x-,

imity with respect to said tooth face portion, means for yieldably urging said element into abrading contact with sai d face portion, and mechanism for drivinglysimultaneously producing said reciprocative and oscillative movements, said mechanism beingso constructedand ar'- ranged as to produce a plr' irali'ty. of said recip rocative movements during each hali cycle of said oscillative movements. F

7. Gear tooth face finishing apparatus comprising relatively oscillatable and reciprocable work and tool support members, means on saidwork .support member for positioning a tooth of a gear having a face portionto be finished for-receiving afinishingoperation, means forconfining-the relative reciprocative movement of said, members to a course extending depthwiseofsald tooth and transversely of the axis of the relative oscillative movement thereof.- an. abrading tool on said tool support; member havingan abrading element engageable with the face portion of opposite sides of saidatoothr respectively anddneluding means for resiliently urging said elements into abrading engagement with'said faceportion, and mechanism for. drivingly simultaneously producing said oscillative movements and a plurality of said reciprocative movements during each half cycle of said oscillative movements.

8. Gear tooth face finishing apparatus comprising relatively oscillatable and reciprocable work and 'tool support members, means on said work support'member for positioning a tooth of said elements into abrading engagement with said faceduring osciilation of said work, and

mechanism for, drivingly simultaneously pro-' during said .reciprocative and oscillatlve movements at respectively independent rates.

9. Gear tooth face finishing apparatus -comprising :tool and worksupport members, mechanism mounting said members for relative oscillatahle movements and stages of relative reciprocaiive movements in transverse directions, means on'said work support member for positioning a tooth of a .gear having opposite face p0r-' tions toJbe finished for receiving a finishing operation, said zmoimting mechanism including means for confining one of said stages of reciprocative movement to a course extending depthwise of said tooth and the other stage of reciprocative movement to a course extending lengthwise of said tooth, an abrading tool on said tool supp rt member having abrading ele- .ments .engageabie with the face portions of opposite sides of said tooth respectively and including means for resiliently urging said ele-- ments into abrading engagement with said face portions, and mechanism for drivingly simultatially parallel to said axis and for positioning a .tooth of said gear having a face to be finished to-receivea finishing operation, a toolsupport' member, an abrading tool shiftably mounted on said toolsupportmemberfor reciprocation transversely of said axis depthwise of said tooth including a pair of abrading elements, each extending iinto overlappin engagement with the face portions of one of the opposite sides of said tooth respectively and having means for urging said elements withsubstantially equal pressure into abrading engagement with said opposite'face portions, and mechanism for drivingly simultaneously producing saidreciprocative and oscillative movements including means for producing a pluralty of said reciprocations depthwise of said tooth duringeachhalfcycle ofsaid osciliative movements ofsaid gear.

11. Gear tooth face apparatus comprising tool and work support members, mecha,aos,ao1 4 anism mounting said members for relative oscillatabie movements and stages of relative reciprocative movements. in transverse directions, means on said work support member for posito he finished for receiving a finishing operation, said mounting mechanism including means for confining one of said stages of reciprocaiive movement. to a course extending depthwise of said tooth and the other stage of reciprocative movement to a course extending lengthwise of said tooth, an abrading tool on said tool support including a pair 01' spring arms each provided with an abrading element forengaging one of the opposite face portions of said tooth respectiveiy, said arms being biased toward each other for yieldably applying said abrading elenients to said face portions, and mechanism for drivingly simultaneously producing said oscillative and said two stages of reciprocative movement.

12. The method of finishing face portions of a gear tooth comprising the steps of producing between an abrading element and a face of a gear tooth simultaneous relative oscillative movements and a plurality of reciprocative movements depthwise of said tooth during each half cycle of said osciilative movements and yieldably urging said face portions and abrading element together. g

13. The method of finishing face portions of a gear tooth which comprises the steps of yieldably urging an abrading element into abrading contact with a face portion of said gear tooth, and producing between said abrading element and face portion simultaneous-relative oscillative movements about the axis of said gear and reciprocative movements both depthwise and lengthwise, respectively of said tooth and at respectively different rates.

14. The method of finishing face portions of said gear tooth, said depthwise reciprocative movements occurring throughout a plurality of cyclm dining each half cycle of said osciliative movements.

' DAVID A. WALLACE. 

